In recent years, a lot of research has been done for a light emitting device which generates incoherent illumination light by emitting, onto a light emitting section including a fluorescent material, excitation light generated by an excitation light source such as a semiconductor light emitting element, e.g., a light emitting diode (LED) or a semiconductor laser (LD: Laser Diode).
An example of a technique relating to such a light emitting device is disclosed by Patent Literature 1.
A light source device of Patent Literature 1 includes (i) a light emitting device capable of preventing a reduction in luminous efficiency and maintaining its performance for a long term and (ii) a light source device including a plurality of light emitting devices. The light source device of Patent Literature 1 moves a fluorescent material layer so as to shift a position of the fluorescent material layer which position is irradiated with excitation light, for the purpose of preventing an increase in a temperature of a fluorescent material.